Android 实现Iphone PickerView 大滚轮效果

/* * Android Wheel Control. * https://code.google.com/p/android-wheel/ * * Copyright 2010 Yuri Kanivets * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package kankan.wheel.widget; import java.util.LinkedList; import java.util.List; import kankan.wheel.R; import android.content.Context; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.graphics.drawable.GradientDrawable; import android.graphics.drawable.GradientDrawable.Orientation; import android.os.Handler; import android.os.Message; import android.text.Layout; import android.text.StaticLayout; import android.text.TextPaint; import android.util.AttributeSet; import android.util.FloatMath; import android.view.GestureDetector; import android.view.GestureDetector.SimpleOnGestureListener; import android.view.MotionEvent; import android.view.View; import android.view.animation.Interpolator; import android.widget.Scroller; /** * Numeric wheel view. * * @author Yuri Kanivets */ public class WheelView extends View { /** Scrolling duration */ private static final int SCROLLING_DURATION = 400; /** Minimum delta for scrolling */ private static final int MIN_DELTA_FOR_SCROLLING = 1; /** Current value & label text color */ private static final int VALUE_TEXT_COLOR = 0xF0000000; /** Items text color */ private static final int ITEMS_TEXT_COLOR = 0xFF000000; /** Top and bottom shadows colors */ private static final int[] SHADOWS_COLORS = new int[] { 0xFF111111, 0x00AAAAAA, 0x00AAAAAA }; /** Additional items height (is added to standard text item height) */ private static final int ADDITIONAL_ITEM_HEIGHT = 15; /** Text size */ private static final int TEXT_SIZE = 24; /** Top and bottom items offset (to hide that) */ private static final int ITEM_OFFSET = TEXT_SIZE / 5; /** Additional width for items layout */ private static final int ADDITIONAL_ITEMS_SPACE = 10; /** Label offset */ private static final int LABEL_OFFSET = 8; /** Left and right padding value */ private static final int PADDING = 10; /** Default count of visible items */ private static final int DEF_VISIBLE_ITEMS = 5; // Wheel Values private WheelAdapter adapter = null; private int currentItem = 0; // Widths private int itemsWidth = 0; private int labelWidth = 0; // Count of visible items private int visibleItems = DEF_VISIBLE_ITEMS; // Item height private int itemHeight = 0; // Text paints private TextPaint itemsPaint; private TextPaint valuePaint; // Layouts private StaticLayout itemsLayout; private StaticLayout labelLayout; private StaticLayout valueLayout; // Label & background private String label; private Drawable centerDrawable; // Shadows drawables private GradientDrawable topShadow; private GradientDrawable bottomShadow; // Scrolling private boolean isScrollingPerformed; private int scrollingOffset; // Scrolling animation private GestureDetector gestureDetector; private Scroller scroller; private int lastScrollY; // Cyclic boolean isCyclic = false; // Listeners private List<OnWheelChangedListener> changingListeners = new LinkedList<OnWheelChangedListener>(); private List<OnWheelScrollListener> scrollingListeners = new LinkedList<OnWheelScrollListener>(); /** * Constructor */ public WheelView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); initData(context); } /** * Constructor */ public WheelView(Context context, AttributeSet attrs) { super(context, attrs); initData(context); } /** * Constructor */ public WheelView(Context context) { super(context); initData(context); } /** * Initializes class data * @param context the context */ private void initData(Context context) { gestureDetector = new GestureDetector(context, gestureListener); gestureDetector.setIsLongpressEnabled(false); scroller = new Scroller(context); } /** * Gets wheel adapter * @return the adapter */ public WheelAdapter getAdapter() { return adapter; } /** * Sets wheel adapter * @param adapter the new wheel adapter */ public void setAdapter(WheelAdapter adapter) { this.adapter = adapter; invalidateLayouts(); invalidate(); } /** * Set the the specified scrolling interpolator * @param interpolator the interpolator */ public void setInterpolator(Interpolator interpolator) { scroller.forceFinished(true); scroller = new Scroller(getContext(), interpolator); } /** * Gets count of visible items * * @return the count of visible items */ public int getVisibleItems() { return visibleItems; } /** * Sets count of visible items * * @param count * the new count */ public void setVisibleItems(int count) { visibleItems = count; invalidate(); } /** * Gets label * * @return the label */ public String getLabel() { return label; } /** * Sets label * * @param newLabel * the label to set */ public void setLabel(String newLabel) { if (label == null || !label.equals(newLabel)) { label = newLabel; labelLayout = null; invalidate(); } } /** * Adds wheel changing listener * @param listener the listener */ public void addChangingListener(OnWheelChangedListener listener) { changingListeners.add(listener); } /** * Removes wheel changing listener * @param listener the listener */ public void removeChangingListener(OnWheelChangedListener listener) { changingListeners.remove(listener); } /** * Notifies changing listeners * @param oldValue the old wheel value * @param newValue the new wheel value */ protected void notifyChangingListeners(int oldValue, int newValue) { for (OnWheelChangedListener listener : changingListeners) { listener.onChanged(this, oldValue, newValue); } } /** * Adds wheel scrolling listener * @param listener the listener */ public void addScrollingListener(OnWheelScrollListener listener) { scrollingListeners.add(listener); } /** * Removes wheel scrolling listener * @param listener the listener */ public void removeScrollingListener(OnWheelScrollListener listener) { scrollingListeners.remove(listener); } /** * Notifies listeners about starting scrolling */ protected void notifyScrollingListenersAboutStart() { for (OnWheelScrollListener listener : scrollingListeners) { listener.onScrollingStarted(this); } } /** * Notifies listeners about ending scrolling */ protected void notifyScrollingListenersAboutEnd() { for (OnWheelScrollListener listener : scrollingListeners) { listener.onScrollingFinished(this); } } /** * Gets current value * * @return the current value */ public int getCurrentItem() { return currentItem; } /** * Sets the current item. Does nothing when index is wrong. * * @param index the item index * @param animated the animation flag */ public void setCurrentItem(int index, boolean animated) { if (adapter == null || adapter.getItemsCount() == 0) { return; // throw? } if (index < 0 || i